Expansion of the Rubber Balloon Filled with Heavy Hydrogen in a Tank of Pure Hydrogen

The expansion of the rubber balloon filled with heavy hydrogen in a tank of pure hydrogen can be explained by the process of diffusion. Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration, resulting in the equalization of concentration.

Initial State:
- The rubber balloon is filled with heavy hydrogen (deuterium), which is an isotope of hydrogen containing one neutron in addition to the usual proton.
- The tank surrounding the balloon is filled with pure hydrogen, which consists of normal hydrogen atoms (protium) without any additional neutrons.

Diffusion Process:
1. Concentration Gradient: Initially, there is a concentration gradient between the heavy hydrogen inside the balloon and the pure hydrogen in the tank. The heavy hydrogen concentration inside the balloon is higher compared to the pure hydrogen concentration in the tank.

2. Permeability of the Rubber Balloon: The rubber balloon is permeable to all isotopic forms of hydrogen. This means that both heavy hydrogen (deuterium) and normal hydrogen (protium) can pass through the balloon material.

3. Diffusion of Hydrogen Atoms: Due to the concentration gradient, hydrogen atoms from the pure hydrogen in the tank start diffusing through the rubber balloon into the heavy hydrogen-filled balloon.

4. Equalization of Concentration: As the hydrogen atoms diffuse, the heavy hydrogen concentration inside the balloon starts to decrease, while the pure hydrogen concentration in the tank increases.

5. Expansion of the Balloon: As the heavy hydrogen concentration inside the balloon decreases, the pressure inside the balloon decreases. At the same time, the pure hydrogen concentration in the tank increases, leading to an increase in pressure outside the balloon. This pressure difference causes the rubber balloon to expand.

Conclusion:
Over time, the rubber balloon filled with heavy hydrogen will expand when placed in a tank of pure hydrogen due to the process of diffusion. The movement of hydrogen atoms through the permeable balloon material equalizes the concentration of heavy hydrogen inside the balloon with the pure hydrogen in the tank, leading to a pressure difference and resulting in the expansion of the balloon.